Who is Daphne from Tides of War: A Novel of Alcibiades and the Peloponnesian War and what is their importance?

Polemides' aunt, Daphne, also serves as his mother figure. She was responsible for arranging his first marriage and serves as his moral compass. When Polemides joins the Spartan army, she threatens to disown him because of his betrayal. In the end, she is unable to do so because of their strong emotional bond.